1. Field of the Invention
The invention refers to a canal bed shell for a sewer or channel consisting at least partially of tubes and carrying a liquid medium.
2. The Prior Art
It is known to build sewers or channels by assembling tubes and to provide between the tubes canal bed shells at least at those positions where cleaning shafts or wells or inspection shafts are to be provided. Such cleaning wells or shafts and inspection shafts are primarily provided at those positions which are subject to become clogged, i.e. for example at the area of side-channel crossings, branchings or more pronounced changes of the direction of the sewer system.
In conventional sewers and channels, respectively, the ends of the tubes carrying the medium and to be connected one to the other by means of the canal bed shell are flush with the side walls of the shaft, the front sides of the canal bed shell bluntly contacting the tube ends. This does, however, not provide a tight connection between the ends of the tubes and the canal bed shells so that there exists the danger that at the connecting area either rising phreatic water or ground water is entering the sewer system or sewage is flowing out of the sewer system. Both phenomena are, however, unfavourable in veiw of the general intention to keep the phreatic water clean.